This invention relates to a document guide and recognition apparatus for machine reading of alpha-numeric characters that appear on the face of a document. It constitutes a manually fed slot reader, where the document is moved longitudinally by the user through a defined path on the equipment in order that its contents might be optically scanned and encoded into a machine readable code. The apparatus constitutes a self-contained remote peripheral which can be coupled to a host processor.
This disclosure specifically relates to physical improvements in the area of the narrow viewing slot through which the document is optically scanned. Paper documents fed through a document slot create dust and small solid particles which tend to physically block the narrow viewing slot for the optical path of the reader. To counteract this, upright ventilation ducts are provided in communication with the illuminating lamps adjacent to the viewing slot. The convection air currents created by the heated lamps are directed through the ventilation ducts and light guiding slots to assure movement of air about the area of the viewing slot. This air movement disperses dust and solid particles and permits such materials to settle on horizontal surfaces of the apparatus remote from the viewing slot.
The purpose of this improvement is to maintain the viewing slot in a clear condition for accurate reading of document information. It also minimizes required servicing of the equipment due to dust problems. Furthermore, the ventilation ducts also maintain the temperature of each lamp at a more constant value, thereby lengthening lamp life.